Towards simulating star formation in the interstellar medium

By A. Slyz, J. Devriendt, Greg L. Bryan, J. Silk. 2004

179 citations recorded by the source corpus.

As a first step to a more complete understanding of the local physical processes which determine star formation rates (SFRs) in the interstellar medium (ISM), we have performed controlled numerical experiments consisting of hydrodynamical simulations of a kilo-parsec scale, periodic, highly supersonic and ”turbulent” three-dimensional flow. Using simple but physically motivated recipes for identifying star forming regions, we convert gas into stars which we follow self-consistently as they impact their surroundings through supernovae and stellar winds. We investigate how various processes (turbulence, radiative cooling, self-gravity, and supernovae feedback) structure the ISM, determine its energetics, and consequently affect its SFR. We find that the one-point statistical measurement captured by the probability density function (PDF) is sensitive to the simulated physics. The PDF is consistent with a log-normal distribution for the runs which remove gas for star formation and have radiative cooling, but implement neither supernovae feedback nor self-gravity. In this case, the dispersion, �s, of the log-normal decays with time and scales with p ln(1 + (Mrms/2) 2 ) where Mrms is the root-mean-squared Mach number of the simulation volume, s = ln � , and � is the gas density. With the addition of self-gravity, the log-normal consistently under-predicts the high density end of the PDF which approaches a power law. With supernovae feedback, regardless of whether we consider self-gravity or not, the PDF becomes markedly bimodal with most of the simulation volume occupied by low density gas. Aside from its effect on the density structure of the medium, including self-gravity and/or supernovae feedback changes the dynamics of the medium by halting the decay of the kinetic energy. Since we find that the SFR depends most strongly on the underlying velocity field, the SFR declines in the runs lacking a means to sustain the kinetic energy, and the subsequent high density constrasts. This strong dependence on the gas velocity dispersion is in agreement with Silk’s formula for the SFR (Silk 2001) which also takes the hot gas porosity, and the average gas density as important parameters. Measuring the porosity of the hot gas for the runs with supernovae feedback, we compare Silk’s model for the SFR to our measured SFR and find agreement to better than a factor two.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/59459d05ed76ca4514fdfd5de60189a3636a1368

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In Astronomy and Astrophysics

1. P. Hopkins
2. Ralf Klessen
3. Volker Springel
4. L. Hernquist
5. A. Dekel
6. T. Naab
7. E. Quataert
8. Mark R. Krumholz

Citations in the corpus

• The Birth of Molecular Clouds: Formation of Atomic Precursors in Colliding Flows (2006, methodology): “We chose a method based on the 2nd order Bhatnagar-Gross-Krook formalism (Prendergast & Xu 1993; Slyz & Prendergast 1999; Heitsch et al. 2004; Slyz et al. 2005), allowing control of viscosity and heat conduction.”
• The Global Evolution of Giant Molecular Clouds. I. Model Formulation and Quasi-Equilibrium Behavior (2006, unknown): “…et al. 2005), include it only from a single source and/or focus on size scales much smaller than an entire GMC (e.g. Dale et al. 2005; Li & Nakamura 2006), or focus on the galactic scale and lack the resolution to say anything about individual GMCs (e.g. Slyz et al. 2005; Tasker & Bryan 2006).”
• The Supernova Rate-Velocity Dispersion Relation in the Interstellar Medium (2005, background): “…been presented in the literature (Rosen & Bregman 1995; Korpi et al. 1999a, 1999b; Gazol-Patiño & Passot 1999; de Avillez 2000; de Avillez & Berry 2001; Avila-Reese & Vázquez-Semadeni 2001; Kim et al. 2001; Kim 2004; de Avillez & Breitschwerdt 2004, 2005; Slyz et al. 2005; Mac Low et al. 2005).”
• The SILCC project - III. Regulation of star formation and outflows by stellar winds and supernovae (2016, methodology): “A recent study by Hennebelle & Iffrig (2014), uses sink particles to more self-consistently model the star formation in such a stratified galactic disc (see also Slyz et al. 2005, for similar work using a periodic box).”
• The chemical history of molecules in circumstellar disks - I. Ices (2009, background): “The gas-phase route towards complex organics involves the hot inner envelope (Td > 100 K), also called the hot core or hot corino in the case of low-mass protostars (Ceccarelli 2004; Bottinelli et al. 2004, 2007).”
• Formation of Structure in Molecular Clouds: A Case Study (2005, methodology): “We chose a method based on the second-order Bhatnagar-GrossKrook (BGK) formalism (Prendergast & Xu 1993; Slyz & Prendergast 1999; Heitsch et al. 2004; Slyz et al. 2005), allowing control of viscosity and heat conduction.”
• Toward First-Principle Simulations of Galaxy Formation: I. How Should We Choose Star-Formation Criteria in High-Resolution Simulations of Disk Galaxies? (2008, background): “…have been a number of studies on this issue (e.g., Vazquez-Semadeni 1994; Scalo et al. 1998; VázquezSemadeni et al. 2000; Wada 2001; de Avillez & Mac Low 2002; Kravtsov 2003; de Avillez & Breitschwerdt 2004; Slyz et al. 2005; Wada & Norman 2007; Tasker & Bryan 2007; Robertson & Kravtsov 2007).”
• Cooling, Gravity, and Geometry: Flow-driven Massive Core Formation (2007, methodology): “…Atomic Line Coolants As in our previous studies of colliding flows, we used the higher-order gas-kinetic grid method Proteus (Prendergast & Xu 1993; Slyz & Prendergast 1999; Heitsch et al. 2004; Slyz et al. 2005; Heitsch et al. 2006, 2007), allowing full control of viscosity and heat conduction.”
• ENZO: AN ADAPTIVE MESH REFINEMENT CODE FOR ASTROPHYSICS (2013, background): “…2003; Lackner et al. 2012; Simpson et al. 2013), galaxy clusters (Loken et al. 2002; Xu et al. 2011; Skillman et al. 2012), the interstellar medium (Slyz et al. 2005), the intergalactic medium (Fang & Bryan 2001; Smith et al. 2011), the circumgalactic medium (Hummels et al. 2013), cooling flows…”
• Simulating the Formation of Molecular Clouds. I. Slow Formation by Gravitational Collapse from Static Initial Conditions (2006, background): “…the gas (e.g. Korpi et al. 1999; de Avillez 2000; Wada 2001; Kritsuk & Norman 2002a,b, 2004; Balsara et al. 2004; de Avillez & Breitschwerdt 2004; Slyz et al. 2005; Joung & Mac Low 2006) have not previously included sufficient chemistry to follow the formation of H2 and so have been unable to…”
• STAR FORMATION IN DISK GALAXIES. I. FORMATION AND EVOLUTION OF GIANT MOLECULAR CLOUDS VIA GRAVITATIONAL INSTABILITY AND CLOUD COLLISIONS (2008, background): “Other groups have studied cloud formation in the context of the local interplay between supernova feedback and a turbulent, multiphase ISM (e.g. Slyz et al. 2005).”
• Self-regulated star formation in galaxies via momentum input from massive stars (2011, methodology): “…L∗/M∗ as a function of age using a STARBURST99 (Leitherer et al. 1999) single stellar population with a Kroupa (2002) IMF at solar metallicity (this time dependence can be important on GMC time-scales, in contrast to models where all energy is coupled instantaneously; see e.g. Slyz et al. 2005).”
• Forming disc galaxies in ΛCDM simulations (2006, background): “…at which SF and feedback happen (a few pc) makes it necessary to develop simplified models to describe SF and subsequent energy feedback from supernovae (SNe) at galactic scales (0.1–1 kpc; Efstathiou 2000; Silk 2001; Wada & Norman 2001; Ferrara 2002; Krumholz & McKee 2005; Slyz et al. 2005).”
• Making Galaxies in a Cosmological Context: The Need for Early Stellar Feedback (2012, background): “In such cases, 4 Myr pass after stars form before the first supernova explodes (some simulations use even longer delays, see Slyz et al. 2005; Dalla Vecchia & Schaye 2012), during which time stars can continue forming without any affect of stellar feedback.”
• Modelling CO formation in the turbulent interstellar medium (2009, background): “…& Pérault 1999, 2000; Koyama & Inutsuka 2000, 2002; Bergin et al. 2004) or on a detailed treatment of the dynamics, but without any treatment of the chemistry (e.g. Balsara et al. 2004; Kritsuk & Norman 2004; Slyz et al. 2005; Hennebelle & Audit 2007; Hennebelle et al. 2008; Banerjee et al. 2009).”
• The SILCC (SImulating the LifeCycle of molecular Clouds) project – I. Chemical evolution of the supernova-driven ISM (2014, background): “…distribution of H2 is consistent with a broad lognormal shape plus a high-density power-law tail, which is expected to develop due to local gravitational collapse (Klessen, Heitsch & Mac Low 2000; Slyz et al. 2005; Kainulainen et al. 2009; Schneider et al. 2011; Girichidis et al. 2014a).”
• Bimodal gas accretion in the Horizon–MareNostrum galaxy formation simulation (2008, background): “Jets have been proposed, and have the advantage of being supported by observations, but shock waves arising from the interaction of the jet with the interstellar medium would tend to push away the hot gas while leaving surrounding clumps of cold gas rather unchanged (Slyz et al. 2005).”
• Multiwavelength analysis for interferometric (sub-)mm observations of protoplanetary disks - Radial constraints on the dust properties and the disk structure (2015, background): “…spectral index β increases with radius: the small values β 1 for R 50 AU signal the presence of dust grains that have reached sizes comparable to 1 mm or more (Natta & Testi 2004), whereas in the outer disk the spectral index approaches β & βISM = 1.7, a signature of the presence of…”